Q3: Two involute gear wheels work with an angle of pressure of 20° and rotate in opposite directions. The smaller wheel has 20 teeth of 5 mm module and rotates at 2000 rev/min. The larger wheel has 80 teeth and is the driven member. If the contact ratio is 1:4, and if the arc of recess is 1-2 times as large as the are of approach, determine: (a) the addenda of the teeth on both wheels, (b) the greatest speed of sliding between the teeth, (c) the center distance of the gears, and (d) the working depth.

Question 1 An epicyclic gear train, as shown in Fig. 1, has a sun wheel S of 30 teeth and two planet wheels P-P of 50 teeth. The planet wheels mesh with the internal teeth of a fixed annulus A. The driving shaft carrying the sun-wheel S, transmits 4 kW at 300 r.p.m. The driven shaft is connected to an arm which carries the planet wheels. 1.1 Tabulate a table of motion for the given epicyclic gear train. 1.2 Determine the number of teeth in gear A, assume module is the same on all the gears. 1.3 Determine the speed of the arm or the driven shaft. 1.4 Determine the torque of the sun. 1.5 Determine the torque of the arm if the overall efficiency is 95 %. Arm S A a. 1 Figure 1: An epicyclic gear train

A straight tooth spur pinion has a 19 tooth pinion rotating at a speed of 1640 rpm. The driven gear will be rotating at a speed of 480 rpm. If the module of the pinion is 2,5 mm and pressure angle is 25 degree; Evaluate the outer diameter (mm) of the gear.

Problem 2: Consider the two gears mounted on the shaft, as shown. Distances are L1 = 100 mm, L2 = 250 mm, and L3 = 175 mm. Diameter of shaft AB is 15 mm, diameter of shaft BC is 20 mm, and diameter of shaft CD is 17.5 mm. Young's modulus for each portion is 200 GPa. Determine the displacement of point D with reference to point A. Also, determine the displacement of point A relative to C. b. Determine the axial strain at any point in shaft segments AB, BC and CD, respectively. If Poisson's ratio for the material of the shafts is v = 0.2, determine the lateral strain in each of the shaft segments. Based on your answers to part (a), do the gears move towards each other, or do they separate from each other? Note that in real gearboxes, movement of gears towards or away from each other is prevented by using thrust bearings. 10 kN 4 kN 5 kN 7 kN 4 kN NY 0I 17.